Brief Answer: DETAILS ARE GIVEN BELOW. Detailed Answer: Hello, Thanks for writing to us. It is quite UNLIKE or RARE to affect your growing embryo from Oyster Poisoning on the day of unprotected sex as fetal Organogenesis starts from 5th week onwards. You should stop taking Oyster and all non-prescribed medications at the earliest to avoid possible birth defect. First trimester is the most vulnerable period for growing fetus and special care needs to be taken. You must undergo one TVS scan around 5 to 6 weeks to get detailed picture on fetal profile. Nuchal Translucency Scan, Triple or Quadruple Test, Fetal Anomaly scan etc are to be done according to gestational age under the guidance of your obstetrician to eliminate gross and minor defect. Take healthy protein added diet with more green vegetables, drink more water for better circulation, take Folic acid & Vitamin Supplement regularly to avoid Neural Tube Defect, avoid heavy work/ long journey and take adequate bed rest. Hope, it helps for your information. Kindly, close the discussion if you don't have any other query. Wish your good health and take care yourself. Regards, Dr Soumen For future query, you can directly approach me through WWW.WWWW.WW

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